DE 10 2007 033 914 A1 describes a radio-device system with a monitoring unit, wherein the monitoring unit is connected to a main-radio device and an emergency-radio device. The status of the main-radio device is evaluated in the monitoring unit. In this context, the monitoring unit analyses commands which are sent to the main-radio device. Checks are carried out to determine whether the command brings about the required change to the status of the main-radio device.
It is sometimes necessary to register a time reference between the receipt of the command in the main-radio device and the changed status of the main-radio device. In particular, this is necessary for the identification of attacks on the main-radio device in order to detect and prevent unauthorized accesses to the main-radio device, for example, with regard to spying on cryptographic keys or depositing false messages. Furthermore, the time reference between the receipt of the command and the change in status of the main-radio device must be monitored in order to check whether specifications for a radio traffic, for example, in accordance with a standard or technical specifications, have been observed or to check internal time specifications for a status change of the main-radio device, so that inferences can be drawn regarding the functional capability of the main-radio device.
What is needed, therefore, is an approach for a radio-device system and a method, in which full functional capability, any error behavior and/or attempted manipulation of the main-radio device can be readily detected.